Acceleration responsive sensor

ABSTRACT

A sensor includes a housing and a base assembly secured thereto. The base assembly includes angularly diverging side walls and an arcuate end wall which cooperatively define a sector shaped recess. A contact member on the base assembly includes a plurality of cantilever spring fingers extending angularly to the sector recess. A pole magnet has its axis coplanar with a bisector of the recess. A resiliently deflectable rod is secured at its upper end thereof to the housing. The lower end of the rod mounts a cylindrical mass movable along a multiplicity of paths within the sector recess. The magnet normally holds the mass in tangential engagement with the side walls of the sector recess. An acceleration pulse of predetermined amplitude and time moves the mass into engagement with one or more of the contact fingers to close a circuit across a source of power, a mechanism to be actuated, the contact member, and the mass.

United States Patent [19] Porter [54] ACCELERATION RESPONSIVE SENSOR[75] Inventor: Glenn A. Porter, Greendale, Wis.

[58] Field of Search ..200/61.45, 61.45 M, 61.48, 200/61.49; 280/150 AB[56] References Cited UNITED STATES PATENTS 2,31 1,637 2/1943 Buchanan..200/6l.49 2,850,291 9/1958 Ziccardi ..200/61.51 X

3,281,551 10/1966 Becke ..200/61.45 R

3,336,045 8/1967 Kobori ..200/61 X 3,410,359 11/1968 Mollison ..180/1033,639,7l0 2/1972 Haruna et al ..200/61.48

3,647,999 3/1972 Mazelsky ..200/61.45 R 3,556,556 1/1971 Goetz..200/61.45 X 2,802,204 8/1957 Kennelly et al. ..200/61.45 M

[ 51 Feb. 20, 1973 Attorney-W. E. Finken et a1.

[57] ABSTRACT A sensor includes a housing and a base assembly securedthereto. The base assembly includes angularly diverging side walls andan arcuate end wall which cooperatively define a sector shaped recess. Acontact member on the base assembly includes a plurality of cantileverspring fingers extending angularly to the sector recess. A pole magnethas its axis coplanar with a bisector of the recess. A resilientlydeflectable rod is secured at its upper end thereof to the housing. Thelower end of the rod mounts a cylindrical mass movable along amultiplicity of paths within the sector recess. The magnet normallyholds the mass in tangential engagement with the side walls of thesector recess. An acceleration pulse of predetermined amplitude and timemoves the mass into engagement with one or more of the contact fingersto close a circuit across a source of power, a mechanism to be actuated,the contact member, and the mass.

8 Claims, 3 Drawing Figures PATHHED ZOI B 3,717,732

1N VEN TOR.

BY awe/@911 ATTORNEY l ACCELERATION RESPONSIVE SENSOR This inventionrelates to pendulum-type sensors and more particularly to such sensorsof the type including a mass supported on a deflectable member formovement between normal and actuated positions in response toacceleration pulses of predetermined amplitude and time applied to themass.

The sensor of this invention is particularly intended for use in avehicle body occupant restraint system. Such systems generally include asource of pressure fluid which inflates an occupant restraint cushionwhenhorizontally deflectable vertical rod, the other end of' whichsupports a mass movable within a sector shaped recess of a base assemblyof the sensor. Another. feature is that the massis movable between anormal position, wherein the mass tangentially engages the angularlydiverging side walls. of the recess adjacent the distal ends thereof,and an actuated positionwherein the mass engages a cantilevered springfinger contact adjacent an arcuate end wall at the proximal ends of suchside walls to close a circuit across a source of power and a mechanismto be actuated. A further feature is that the mass is held in normalposition by a pole magnet having itsaxis coplanar with the bisector ofthe recess. Yet another feature is that the housing is tubular and thedeflectable rod supporting the mass is coaxially mounted within suchhousing. Yet afurther feature is that the mass is cylindrical and oneperipheral edge thereof slidably engages the cantilevered spring fingerwhich extends angularly to the recess. Still another feature is that thebase assembly includes a pair of circular plates of insulating materialwhich cooperatively define the-sector shaped recess. Still afurtherfeatureis that the pole magnet is co operatively housed withinsemicylindrical embossmentsof the housing and a cover plate secured tothe housing and securing the base assembly plates and the housing toeach other.

These and other'features of thesensor of this invention will be readilyapparent from the following specification and drawings wherein:

F IG..I isa sectional view of a sensor according vto this invention withthe rod and mass being shown.in full lines in normal position and inphantom lines in actuated position;

FIG. 2 is a sectional view taken plane indicated by line 22 of FIG. 1';and

FIG. 3 is a sectional view taken generally along the plane indicated byline 3-3 of FIG. 1..

Referring now to the drawings, a sensor designated generally accordingvto this invention includes a tu bular housing 12 and a base assembly-14. The housing generally along the 12 includes a loweroutwardly flaringcircular flange l6 and an upper dome wall 18 having an upwardly flangedcentral aperture 20, the axis of which is coaxial with the axis of thehousing. A deflectable rod 22 is received through the aperture 20.,andsuitably secured to the flange defining such aperture such as bywelding. The

lower end of the rod extends into, and is secured to a cylindrical mass24 of predetermined weight. Thus, normally, the axis of the rod 22 andof the weight 24 is coaxial with'the axis of the housing 12.

The base assembly 14 includes upper and lower circular plates 26 and 28of insulating material. Generally, the plates are of the same extent asthe flange 16. The upper plate 26 includes a circular recess 30 and thelower plate 28 includes a sector shaped recess 32 which opens to astepped radial slot 34. A spring contact 36 includes a base portion 38provided with a pair of spaced apertures 40 which receive embossments 42of the upper plate 26. These embossments are also received withinapertures 44 of the lower plate 28 to thereby index the plates 26 and 28with respect to each other and in turn index the contact 36 with respectto these plates. The contact 36 includes a plurality of angularly.extending cantilevered spring fingers 46 which extend through the sectorshaped recess 32 and past a portion 48, FIG. 2, of'the circular recess30 of the plate 26. The portion 48 of the circular recess cooperateswith the side walls 50 of the recess 32 to define a sector shaped recesswithin which the mass 24 is movable.

A pole magnet 52 is received within the stepped radial slot 34 of plate28 and also within cooperating semicylindrical embossments 54 and 56 ofthe flange 16 of housing 12 and a cover plate 58. The stepped slot 34and recess 30 cooperatively locate the magnet radially with respect toplates 26 and 28. Slot 34 also'locates the magnet with its axis coplanarwith a bisector of the recess 32. The embossments 54 and 56 locate themag-' net with respect to the plane of the recess 32 and also verticallywith respect to the cover plate 58 and the housing 12. A segmentedreturn bent flange 60 of the cover plate 58 engages the plate 28 andflange 16 to' secure the base assembly 14 and the housing 12 to eachother and to the plates 26' and 28. The cover plate 58 includes acentral cylindrical embossment 62, FIG. 1, which provides for freedom ofmovement of the mass 24.

In normal position, as shown in full lines in FIG. 1 and in FIG. 2, themass 24 is located in tangential engagement with the side walls 50 ofrecess 32 by the magnet 52 and the rod 22 is coaxial with the housing12. Upon an acceleration pulse of predetermined amplitude and time beingapplied to the mass within a predetermined zone of response, the mass 24moves to the right as shown in phantom lines in FIG. 1 to actuatedposition and engages one or more of the spring fingers 46. The engagedfingers are deflected downwardly bya peripheral edge of the mass tocushion and stop the, movement thereof. The rod 22 and the contact plate36 are connected across the source of power such that engagement of themass and one or more of the fingers 46 completes a circuit across suchsource of power and a mechanism to be actuated or electrically fired bythe sensor. Should the pulse be sufficiently great, the mass will engagethe arcuate portion 48 of recess 30 to limit movement of the mass andavoid permanent deformation of the engaged fingers 46.

In the embodiment shown, the walls 50 of recess 32 define an includedangle of 74. This angle is less than the zone of response, of the sensor10 and is set in a manner disclosed in copending application, Ser. No.

173,806, Sensor, Rodney A. Brooks and Vincent A.

Orlando filed Aug. 23, 1971, and assigned to the assignee of thisapplication.

Thus, this invention provides an improved sensor.

lclaim: y

l. A sensor comprising, in combination, a housing, a base assemblyincluding angularly related side walls defining a sector shaped recessopening to the housing, means securing the housing and base assembly toeach other, a contact member including at least one cantilever springfinger extending angularly to the recessintermediate the distal ends ofthe side walls, a resilient member extending through the housing, meansmounting the resilient member adjacent one end thereof to the housing, amass secured to the other end of the resilient member and having atleast a portion thereof movable along a multiplicity of paths within thesector shaped recess, and a magnet mounted on the base assembly adjacentthe proximal ends of the side walls and having its axis coplanar with abisector of the recess, the magnet magnetically holding the mass inengagement with the side walls of the recess adjacent the proximal endsthereof, an acceleration pulse of predetermined amplitude and timeovercoming the magnetic attraction of the magnet and moving the masstoward the spring finger and into engagement therewith to close acircuit across a source of power connected to the mass and springfinger.

2. The combination recited in claim 1 wherein the housing includes anarcuate end wall at the distal end of the side walls, the engagement ofthe mass with the arcuate end wall limiting movement of the mass to lessthan that which would result in permanent deformation of the springfinger.

3. A sensor comprising, in combination, a housing, a base assemblylocated at the lower end of the housing and including angularly relatedside walls defining a sector shaped recess opening to the housing, meanssecuring the housing and base assembly to each other, a contact memberincluding at least one cantilever spring finger-extending angularly tothe recess intermediate the distal ends of the side walls, a resilientmember extending through the housing, means mounting the resilientmember adjacent the upper end thereof to the housing adjacent the upperend thereof, a cylindrical mass secured to the lower end of theresilient member and movable along a multiplicity of paths within thesector shaped recess, and a magnet mounted on the base assembly,adjacentthe proximal ends of the side walls and having its axis coplanar with abisector of the recess, the magnetic attraction of the magnet holdingthe mass in tangential engagement with the side walls of the recessadjacent the proximal ends thereof, an acceleration pulse ofpredetermined amplitude and time overcoming the magnetic attraction ofthe magnet and moving the mass toward the spring finger and intoenrecess.

6. The combination recited in claim 3 wherein a cylindrical peripheraledge of the mass engages and deflects the spring finger, the resilientlydeflectable member being deflected upon movement of the mass andcooperating with the spring finger in exerting a force on the massreturning the mass to normal position.

7. A sensor comprising, in combination, a vertical tubular housing, abase assembly at the lower end of the housing including angularlyrelated side walls defining a sector shaped recess opening to thehousing, a contact member including at least one resiliently deflectablespring finger extending angularly to the recess intermediate the distalends of the side walls means indexing the housing, base assembly andcontact member to each other, means securing the housing, base assembly,and contact member together in indexed relationship, a resilientlydeflectable member extending through the housing, means mounting theresiliently deflectable member adjacent the upper end thereof to thehousing adjacent the upper end thereof, a cylindrical mass secured tothe lower end of the resiliently deflectable member and movable along amultiplicity of paths within the sector shaped recess, and a magnetmounted on the base assembly adjacent the proximal ends of the sidewalls and having its axis coplanar with a bisector of the recess, themagnet magnetically holding the mass in engagement with the side wallsof the recess adjacent the proximal ends thereof, an acceleration pulseof predetermined amplitude and time overcoming the magnetic attractionof the magnet and moving the mass toward the spring finger, a peripheraledge of the mass engaging the spring finger to close a circuit across asource of power connected to the mass and spring finger, the resilientlydeflectable member and spring finger each being resiliently deflectedupon engagement thereof.

8. A sensor as recited in claim 7 wherein the base assembly includesmeans indexing the magnet with its axis coplanar with the bisector ofthe recess.

1. A sensor comprising, in combination, a housing, a base assemblyincluding angularly related side walls defining a sector shaped recessopening to the housing, means securing the housing and base assembly toeach other, a contact member including at least one cantilever springfinger extending angularly to the recess intermediate the distal ends ofthe side walls, a resilient member extending through the housing, meansmounting the resilient member adjacent one end thereof to the housing, amass secured to the other end of the resilient member and having atleast a portion thereof movable along a multiplicity of paths within thesector shaped recess, and a magnet mounted on the base assembly adjacentthe proximal ends of the side walls and having its axis coplanar with abisector of the recess, the magnet magnetically holding the mass inengagement with the side walls of the recess adjacent the proximal endsthereof, an acceleration pulse of predetermined amplitude and timeovercoming the magnetic attraction of the magnet and moving the masstoward the spring finger and into engagement therewith to close acircuit across a source of power connected to the mass and springfinger.
 1. A sensor comprising, in combination, a housing, a baseassembly including angularly related side walls defining a sector shapedrecess opening to the housing, means securing the housing and baseassembly to each other, a contact member including at least onecantilever spring finger extending angularly to the recess intermediatethe distal ends of the side walls, a resilient member extending throughthe housing, means mounting the resilient member adjacent one endthereof to the housing, a mass secured to the other end of the resilientmember and having at least a portion thereof movable along amultiplicity of paths within the sector shaped recess, and a magnetmounted on the base assembly adjacent the proximal ends of the sidewalls and having its axis coplanar with a bisector of the recess, themagnet magnetically holding the mass in engagement with the side wallsof the recess adjacent the proximal ends thereof, an acceleration pulseof predetermined amplitude and time overcoming the magnetic attractionof the magnet and moving the mass toward the spring finger and intoengagement therewith to close a circuit across a source of powerconnected to the mass and spring finger.
 2. The combination recited inclaim 1 wherein the housing includes an arcuate end wall at the distalend of the side walls, the engagement of the mass with the arcuate endwall limiting movement of the mass to less than that which would resultin permanent deformation of the spring finger.
 3. A sensor comprising,in combination, a housing, a base assembly located at the lower end ofthe housing and including angularly related side walls defining a sectorshaped recess opening to the housing, means securing the housing andbase assembly to each other, a contact member including at least onecantilever spring finger extending angularly to the recess intermediatethe distal ends of the side walls, a resilient member extending throughthe housing, means mounting the resilient member adjacent the upper endthereof to the housing adjacent the upper end thereof, a cylindricalmass secured to the lower end of the resilient member and movable alonga multiplicity of paths within the sector shaped recess, and a magnetmounted on the base assembly adjacent the proximal ends of the sidewalls and having its axis coplanar with a bisector of the recess, themagnetic attraction of the magnet holding the mass in tangentialengagement with the side walls of the recess adjacent the proximal endsthereof, an acceleration pulse of predetermined amplitude and timeovercoming the magnetic attraction of the magnet and moving the masstoward the spring finger and into engagement therewith to close acircuit across a source of power connected to the mass and springfinger.
 4. The combination recited in claim 3 wherein the housingincludes an outwardly flaring circular flange at its lower end seatingthe base assembly, the sensor including means clamping the flange of thehousing to the base assembly to assemble the sensor.
 5. The combinationrecited in claim 3 wherein the base assembly includes integral meansradially spacing the magnet with respect to the mass and indexing themagnet with its axis coplanar with a bisector of the recess.
 6. Thecombination recited in claim 3 wherein a cylindrical peripheral edge ofthe mass engages and deflects the spring finger, the resilientlydeflectable mEmber being deflected upon movement of the mass andcooperating with the spring finger in exerting a force on the massreturning the mass to normal position.
 7. A sensor comprising, incombination, a vertical tubular housing, a base assembly at the lowerend of the housing including angularly related side walls defining asector shaped recess opening to the housing, a contact member includingat least one resiliently deflectable spring finger extending angularlyto the recess intermediate the distal ends of the side walls meansindexing the housing, base assembly and contact member to each other,means securing the housing, base assembly, and contact member togetherin indexed relationship, a resiliently deflectable member extendingthrough the housing, means mounting the resiliently deflectable memberadjacent the upper end thereof to the housing adjacent the upper endthereof, a cylindrical mass secured to the lower end of the resilientlydeflectable member and movable along a multiplicity of paths within thesector shaped recess, and a magnet mounted on the base assembly adjacentthe proximal ends of the side walls and having its axis coplanar with abisector of the recess, the magnet magnetically holding the mass inengagement with the side walls of the recess adjacent the proximal endsthereof, an acceleration pulse of predetermined amplitude and timeovercoming the magnetic attraction of the magnet and moving the masstoward the spring finger, a peripheral edge of the mass engaging thespring finger to close a circuit across a source of power connected tothe mass and spring finger, the resiliently deflectable member andspring finger each being resiliently deflected upon engagement thereof.